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Transcript: An astrometric binary occurs when a bright star is moving around an unseen companion. In this case the orbit is detected and measured based on the astrometric motion of a single star. This requires extremely careful positional measurements, usually with an accuracy of a thousandth of an arcsecond or less, and careful observations over several months. Astrometric binaries are an important category of binary stars because in many cases binary stars combine an object of intrinsically low luminosity, such as a dwarf or a cool main sequence star, with an intrinsically highly luminous star, such as a hot main sequence star or a giant or supergiant.
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חיפוש פרקים ישנים
חפש פרקים קודמים של 17. Galactic Mass Distribution and Galaxy Structure.
פרקים אחרים בפודקאסט הזה
Transcript: Consider a binary system where a giant or a supergiant star is in orbit around a white dwarf and where a mass transfer between the lobes pushes the white dwarf over the Chandrasekhar limit. At this point the white dwarf collapses catastrophically to form either a neutron star or a bla…
Transcript: Consider a binary pair where the more massive star has expanded to fill its Roche lobe, and the smaller star is a white dwarf of nearly 1.4 solar masses. As the massive star dumps hydrogen onto the white dwarf the gas is compressed, rapidly heated, and it ignites nuclear reactions tha…
Transcript: It’s a great challenge to determine the true incidence of binary and multiple star systems. The nearest stars are well observed, but it’s a very small sample. As we go to more distant stars a faint companion might not be detectable. Spectroscopic binaries are biased towards small se…
Transcript: Most binary stars orbit slowly with a large distance between the two stars. However, a small fraction of binary systems are in close, tight, rapid orbits. In this situation mass transfer can occur from one star to the other. The system of two co-orbiting stars is surrounded by two t…
Transcript: How does mass transfer occur in a close binary pair? The Roche surface or lobes define the region of space where gas is bound to one or both stars. If either star becomes a giant the outer layers swell to fill the lobe, and the teardrop shape becomes the actual surface of the star. …
הצהרה: הפודקאסט והגרפיקה המוטבעים בדף זה הם מ-Dr. Christopher D. Impey, Professor, Astronomy, שהוא רכושו של בעליו ואינו קשור או מאושר על ידי Listen Notes, Inc.
